When sleeping at night, drivers of large trucks that operate over long distances and travel for many days often utilize sleeper compartments built into their truck cabin. This reduces the cost of lodgings while allowing truckers to sleep in rest areas on highways, thereby eliminating the need to detour off their routes to find and return from overnight lodging. Maintaining comfortable cabin temperatures during warm evenings, however, often means running the truck engine throughout the night to power the truck air conditioner. This uses considerable fuel, decreases engine life by continual operation, provides a continual source of environmental pollutants, and diminishes driver health by exposing the driver to elevated levels of the pollutants during sleep. In addition, the continuous vibration increases mechanical fatigue on truck tractor components, thereby decreasing time between repairs. Not running a truck air conditioner can lead to increased driver fatigue due to poor sleep or increased operating costs (use of motels/hotels).
Military vehicles such as tanks or armored personnel carriers must also run vehicle engines or auxiliary power units to maintain internal air conditioning. Providing an auxiliary cooling system that does not rely on diesel fuel presents a smaller infrared signature and improves battlefield survivability.